Surface hardening machine



NOV' l1, 1952 R. J. CLARCQ, JR., E-r A1. 2,617,643 r SURFACE HARDENING MACHINE Filed March 18,1950 w 2 SHEETS-SHEET z Ano4 FIG. 5

INVENTOR.

RICHARD J. CLARCQJR,

CARL E. ERNST Patented Nov. 1v1, 1952 Ernst, Brighton, N. Y., assignor'sf to Gleason' gvoxiks, Rochester, N. Y., a corporation of New for' f -pplicationMarch 18, 1950,Serial No.l1`50,476

.'Ihe" present invention relates to apparatus for surface-hardening gears and more particularly to 'machines for. 'surface-hardening' bevel and' hypoid gears.

In conventional machines for hardening gears, hardening is` effected hy traversing a torch or a pairof torches. along. the' length of a tooth and immediately' quenching. the heated tooth by' spraying. oil or Water on it, or allowing it to air" harden'.` The travel' of the torches can be' adjusted for' any predetermined speed, either uniform. or' varying.

The teeth'f of: bevel and hypoid' gears, ordinarily decrease in thickness' and in height from theiry outer to their inner ends. In conventional machines for hardening such gears', therefore, the travely ofthe torch or torchesis accelerated. as the torches move from the large end tothe small end' of al tooth, and' the torches are also moved' in' paths converging' from the large to the' small erld ofiA the tooth. The purpose is 'to raise the tooth to a' uniform temperatureV all along itsI length' as closely as possible so as to obtain as nearly` 'as' possible' uniform hardening al'ongl the tooth. f

'In machines' as' heretofore constructed, however;` there has been' no way to compensate for variations' in' the rate of heat absorption`v by the' Work' due to variations in the volume of metal adjacent to the`r tooth being heat-treated. The

rapidity with' which the'. tooth, that is to be hardened,` reaches' its critical temperature is' strongly' aiected by the rate of absorption of the- Yheat into' adjacent parts which are not to"y bef heat treated. It isv obvious that' a part of' ai tooth to b'e hardened requiresA a shorter period under the name in order to reachits critical" temperature, if the adjacent sections ofA the workpiece. are' thin and cannot carry the' heat' away quickly, than another part of a tooth whiclfrv ifs` adjacent' parts that' are thicker and that have, therefore, greater` capacity for carry-v ing: away the heat'. Heretorore it has been a matter of judgment' and of manual' adjustment in' setting the ma; chine to' obtain the liest results possible' in' varying.: the speed Vof travel of' the torches 'in' confornity with the rate of' heat absorption'. If there isv a. variation in. the intensity ofthe flame, however, even under the best of conditions, the result is anV improperly heat-treated piece.

"The primary object" of` the present invention feto provide means'v for controlling. automatical lyfthe speedvof. travel of the torches in a sur-V face-hardening machine so as' to obtain uniform intensity ofthe heatA4 all along the length of' a gear tooth or other part, which is to be' hardened.. regardless of variation in shape of the tooth along its length andv regardless off the shape and' heat absorption characteristics' of` the` parts adjacent to the' tooth.

Another` object of the invention is to provide controlv mechanism for a machine for' surfacehardening gear teeth and' the like in' which' uniformityof heatftreatment all along'the length of" ar tooth may be obtained regardless' of any' variation in the intensity of the' lame during' the travel' of the torch along the length o'f the" tooth. j

A further oioj'ectof thel invention is' to provide a control mechanism for' the' speedv of travel ofthe torches in. a surface-hardening machine' through which; the machine may be set up entirely byv gauges, and no vjudgment on the part" of the operator in determining the' speed of move ment' will be required.

Other'fobj'ects of' theinvention will be" ap'- pa'rent hereinafter from' the' specification andv from the recital' of the' appended claims.

The' invention has been shown as' applied' to a machine of the general type disclosed' in the" Slade'U s; Pat-ent No.` 2,102,040, granted December' 14,-` 1937', but iti is not. restricted'to' such use".

In the drawings: v

Fig. l is a side elevation of'a surface-hardening' machine ofthe generaly type shown in the Slade" patent' above'v mentioned but' modified in` ac-V cor'dance with the prinlcples ofj the' present' in-` vention.;A Y

Fig.; 2 is a diagrammatic viewV illustrating the construction and principle ofA operation of this" modified form of machine;

Fig. 3 isV a side elevation showing thel control' vgauge of' the' machine and th'e gearingl which" connects this `gauge tothe control valve Fig. 4 is' a plan View showing the two torches' of the machine, and the' gauge for' setting the'I positions ofthe controlling py'rometerv relativeV to the torches;l and Fig.-5' is a side-elevation of'v this setting` gauge.

Referring now to' the drawings by numerals of reference, l0' denotes the base of the machine', while H and. l2" designate two columns. which project: upwardly from the base. The gear G, which is to be hardened, is adapted. to be. mounted upon the top ofA the column ll. IIlhe` distance of the work above the` base of the machine' can'be adiusted, as is requiredl for gears of different' sizes and differenttypes', by' use' of internesti''ng only a fragment of which is shown in Fig. 2.

The gas mixture is supplied to this pipe in any suitable way.

The torches are adapted to move in the hardening operation along the length of each tooth from one end thereof to the other. For preheating a tooth the torches may be moved rapidly from the small end to the large end of the tooth, but for the hardening operation they are preferably moved slowly from the large to the small end of the tooth. The sides of a tooth are quenched immediately after they are heated to the hardening temperature, and as the torches move progressively along the tooth from one end to the other, by spraying jets of water on the tooth.` To

this end, a pair of spray pipes 22 are provided. These pipes are bent at their delivery ends to direct the liquid used as the quenching medium on the tooth surfaces `at points immediately behind the torches. The pipes 22 are also secured in the blocks I8. These pipes are connected by means of flexible hoses 24 with a manually operable valve 25' to which the water is supplied by a pipe 26, which is shown only fragmentarily.

The blocks I8 are slidable transversely in ways formed in the head 25 of a ram 21. They are `pressed outwardly by a spring L29 and carry at their outer ends rollers 28 which ride on guide rails 3l. These guiderails are adjustable angularly in accordance with the taper in width from end to end of the teeth of the gear to be hardened so that the torches and quenching jets may remain at substantially uniform distances from opposite sides of a tooth as they travel, under actuation of the ram, from one end of the tooth to the other. n

Theram 21 reciprocates in ways formed in a supporting bracket 30. This .bracket is 4trunnioned by means of a pin 32 on the head of a cylinder 33 which is carried by the column I2.

, A `worm which is secured to a manually operable shaft 35 and which engages with a worm wheel segment (not shown) that is secured to the rocker member 30 serves for effecting angular adjustment of the rocker member to position the torches at the correct angular relationship to the 'work in accordance with the pitchcone angle thereof.

Mounted upon an extension 31 of the bracket 30 is a cylinder 40. Reciprocable in this cylinder is a piston 4I. This piston is secured to one end of a piston rod 42 which projects through one end plate 43 of the cylinder and which is connected at its opposite end to the ram 21.

VThe direction of movement of the piston 4I and of the Vram 21 is controlled by a valve 4 5'which is reciprocable in a valve casing 45. The valve 45 is constantly urged to the right in the casing 46 by a coil spring 41 which surrounds the valve stem 48 and which is interposed between'the left hand en d wall of the casing and the collar portion 49 ci the valve. The valve is shifted manually in the opposite direction by a hand-lever 5S. This lever ispivoted at 5I on a plate 52 which is formed integral with the valve casing 4S. This lever is connected with the valve stem 4a by a unk 53.

The valve is adapted to be releasably locked in the position to which it is moved manually. For this purpose the lever 50 is formed with a lug 55. rI'his is adapted to be engaged by a lock-dog 51. The lock dog 51 is pivotally mounted on a bracket 58 which extends from the casing 46. The lockdog is constantly pressed ytoward locking position by a spring-pressed plungerA 59 which is housed in the bracket 58.

`When the valve 45 is in the position shown, the pressure fluid, which is supplied from the pipe BU, flows through the duct 6I to the right hand end Vof the cylinder 4D, and the left hand end of this cylinder is on' exhaust through the duct 62 and theI ducts. .'The parts are shown in Fig. 2 at the end of the hardening stroke of the ram 21.

In the hardening stroke, the rate of movement of the ram is controlled by a throttle valve 65.

YSofaras has been described, the machine of the present invention is constructed and operates like the machine disclosed in the Slade patent above mentioned; and reference may be had to that patent for a more detailed description of the construction and operation of the several parts so far described herein. y

In the machine disclosed in the Slade patent the throttle valve is cam-actuated. In the machine of the present invention, the throttle valve 65 is 'controlled automatically from the temperature of the workpiece which is being hardened and more specifically from the temperature along the length of the tooth as the tooth is heated up along its length. For this purpose there is mounted between the two burners I5 the thermocouple 61 of a conventional pyrometer. This thermocouple is carried by anarm fwhich is secured Vin the ram 21. l The thermocouple isr operatively connected with a dial thermometer 10 by lines 1 I. The dial ther.-` mometer has a needle 12 which reads against the graduations provided on'the dial. The dial thermometer is also connected through gearing '13,y 14 with a shaft V15 to which is secured a rotary valve 18. This valve rotates in a casing 11. Airv is supplied to this casing from a line 18. It is' exhausted from the ,casing through a line 19. In the position shown in Fig. 2, the airpasses through the duct 88 in the valve -16 toa line 8 I which leads: to Athe Vupper end. of a casing 82 in which is, mounted a piston 83. A coil spring 84,'whichI surrounds the rod 85, that is secured toY this' pis-l ton, constantly presses the piston upwardly. The' rod S5 is connected through a suitable coupling 86 androd 81 to the throttle valve 65. f ...l The lfthermoc'ouple.'61 is positionedto be' ad-lA jacentV the top of thev tooth, which isb'eing hardened,^and travelsunder actuation of ,ram 21 alongl the top of thetooth from one end' thereof tof, the other as the torches 'I5 travel along the sidesn of the tooth andheat'up the tooth. Hence, as

f the pis-t0nV 4I travels .from right' to- 4leftin the hardening stroke, Ithe pyrometerco'ntrols .the speed of that travel.l The travelis controlled, moreover, in such wise that.A all-,"parts oithetooth from endto .end are heate'dft.' a' 'desired y uniform temperature.i `Of course, a p'art which is of'` thinner section or smaller height will heat faster' than a part which is of thicker sectionA or greater height. uHence, the speed of travel of theV ram. will be accelerated during hardening of the thinner-sectioned, small-height part of theA tooth. The pyrometer will byagaugirngjthe temperaturev jofu the Vtoothl turn the -valve 16 in'one direction jor i other jas required, as the'torchesf move alongthelengthjof a tooth-, solthat all parts disengage that detent from the dog 55.

5 of the tooth from end to end will be heated to a uniform desired temperature. Rotation of the valve 16 controls the air supply to the cylinder 82, thereby controlling the position of the throttle valve B5, which, in turn, controls the rate of exhaust of the hydraulic motive fluid through duct 63 from the left hand end of the cylinder 40, thereby controlling the rate of movement of ram 21 and torches l5. The duct 63 is connected by the throttle valve 65 with an exhaust duct 89 that leads to the sump 90 of the machine.

At the end of the hardening stroke, the work can be indexed, and the valve 45 can be reversed to produce a return or preheating movement of the ram 21, by shifting the lever 50 clockwise about its pivot 5I. The lock-dog 51 then engages and holds the lever in this latter position until the end of the return movement of the piston l I The trip dog 95, which isadjustably mounted upon the piston rod 42, engages the detent 51 at the end of the return stroke of piston 4I, to The spring 41 then shifts the valve 45 back to the position shown in Fig. 2; and a new hardening stroke begins automatically.

For best results, the thermocouple 61 must be positioned accurately between and with reference to the two torches I5. For this purpose a setting gauge may be used such as shown in Figs. 4 and 5. This gauge has a body portion from which project two parallel arms IOI that have portions |02 at their free ends bent at right angles to engage the front faces of the torches l5. The bracket also carries a rod I 06 which is adapted to abut against the thermocouple 61. The bracket |00 is carried by a bar 104 which may be positioned within a socket (Fig. 1) of the machine,

While the invention has been described in cont nection with a particular embodiment thereof, it

is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described our invention, what we claim is:

l. A surface hardening machine for hardening gear teeth comprising a work support, a reciprocable ram, a pair of laterally spaced torches mounted on said ram in positions to direct flames at opposite tooth sides of the work at substantially laterally aligned areas of said opposite tooth sides, means for actuating the ram to move lthe torches longitudinally along said top of the tooth sides, a temperature-sensitive element mounted on the ram laterally between the two torches to be adjacent the tooth being hardened and to be disposed in approximate lateral alignment with said torches to sense the part of the tooth being heated by said torches, and means operatively connecting said element to the means for moving the ram to control the rate of movement of the ram.

2. A surface hardening machine for hardening gear teeth comprising a work support, a reciprocable ram, a pair of laterally spaced torches mounted on said ram in positions to direct flames at opposite sides of a tooth of the work at substantially laterally aligned areas of said opposite tooth sides, a temperature-sensitive element mounted on said ram laterally between said torches and adjacent the top of the tooth being hardened and disposed in approximate lateral alignment with said torches to sense the part of the tooth being heated by the torches, fluid-pressure operated means for moving said ram to move said torches longitudinally of the tooth, a throttle valve controlling the rate of said movement, and means operatively connecting the throttle valve to said element to vary the position of the throttle valve under control of said element.

3. A surface hardening machine for hardening gear teeth comprising a, work support, a reciprocable ram, a pair of laterally aligned blocks mounted on said ram to be movable transversely thereof, a torch secured in each block, the two torches being positioned to direct flames at opposite sides, respectively, of a tooth of the work, a temperature-sensitive element mounted on the ram to be adjacent the top of the tooth of the work and to be disposed in approximate lateral alignment with said torches to sense the part of the tooth being heated by the torches, fluidpressure operated means for moving the ram to travel the torches longitudinally along the sides and said element longitudinally along the top of a tooth being hardened, a throttle valve for controlling the rate of movement of the ram, duid-pressure operated means for moving said valve, a movable valve for controlling the lastnamed means, a pyrometer actuated by said element, and means operatively connecting said pyrometer to said last-named valve to control the position of said last-named valve.

RICHARD J CLARCQ, JR. CARL E. ERNST.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,067,549 Sykes Jan. 12, 1937 2,102,040 Slade Dec. 14, 1937 2,194,909 Moss et al. Mar. 26, 1940 2,220,002 Rollman et a1 Oct. 29, 1940 2,407,230 Furkert Sept. 10, 1946 FOREIGN PATENTS Number Country Date 445,425 Great Britain Apr. 8, 1936 

